ES2807885T3 - Reactive power controller to control a reactive power in a wind farm - Google Patents

Abstract

A reactive power controller to control a reactive power in a wind farm network connected to a power supply network and comprising at least two sub-networks (300, 400, 500) and a collector part (905), in which At least two wind turbines (301, 401, 501) are connected to each sub-network of the at least two sub-networks, in which the at least two sub-networks are connected to the collector part (905) and in which the collecting part establishes the connection with the power supply network, the reactive power controller comprising: at least one sub-network measurement device (701, 702, 703) arranged in each sub-network, to measure a power component reactive in each sub-network (300, 400, 500); at least one sub-network controller (801, 802, 803) operatively connected to the at least one sub-network measurement device (701, 702, 703) to control said at least two wind turbines (301, 401, 501 ) connected to the sub-network based on the reactive power component measured in each sub-network (300, 400, 500) in such a way that a desired reactive power value is reached in each sub-network; wherein at least one sub-network controller (801. 802, 803) is connected to individual wind turbine controllers of wind turbines (301, 302, 303) connected to the sub-network; a determining device (700) for determining an actual reactive power value in the collecting portion (905); and a wind farm controller (800) operatively connected to the determining device (700) to control at least one of the at least one sub-network controller (801, 802, 803) based on the actual reactive power value determined in the collecting part (905), such that a desired reactive power value is reached in the collecting part (905); and wherein each sub-network (300, 400, 500) includes an associated sub-network transformer (321, 421, 521) used to transform the energy generated by the individual sub-networks (300, 400, 500) of medium voltage to a high voltage range; and wherein the wind farm controller (800) is used to control individual sub-network controllers (801, 802, 803) that control respective wind turbines in the associated sub-network (300, 400, 500), and wherein current and voltage measurements are made by the sub-network measurement devices to measure reactive power components on each sub-network side of the respective sub-network transformers (321, 421, 521) and in which the part collector (905) comprises a bus bar (600) and a tap point (706) is provided between said at least two sub-networks (300, 400, 500) and said bus bar (600) and a complete compensation or partial (Qcomp) of reactive power components (Q) near the tap point (706) on the bus bar (600) by means of the reactive power values reached in each sub-network.

Description

DESCRIPTION

Reactive power controller to control a reactive power in a wind farm

The subject matter described in this document relates generally to systems for operating a plurality of wind turbines in a wind farm and, more particularly, to systems for controlling a reactive power generated in the wind farm.

In general, a wind turbine includes a turbine that has a rotor that includes a rotating hub unit that has multiple blades. The blades transform the wind energy into a mechanical torque that drives one or more generators through the rotor. The generators are sometimes, but not always, rotatably coupled to the rotor through a gearbox. The multiplier increases the inherent low rotational speed of the rotor so that the generator efficiently converts mechanical rotational energy into electrical energy, which is supplied to a power supply network through at least one electrical connection. There are also direct drive wind turbines without a gearbox. The rotor, generator, gearbox and other components are usually mounted inside a casing, or nacelle, which is located on top of a base that can be a tubular structure or tower.

Some wind turbine configurations include double-fed induction generators (DFIGs). Such configurations can also include power converters that are used to convert a frequency of the generated electrical energy to a frequency substantially similar to the frequency of the electrical network. Furthermore, such converters, together with the DFIG generators, also transmit electrical energy between the power supply network and the generator, as well as transmit an excitation energy of the generator to a wound generator rotor from one of the connections to the connection of the power supply network. On the other hand, some wind turbine configurations include, among other things, alternative types of induction generators, permanent magnet (PM) synchronous generators, and electrically excited synchronous generators and switched reluctance generators. These alternative configurations can also include power converters that are used to convert the frequencies as described above and transmit electrical power between the utility grid and the generator.

Known wind turbines have a plurality of mechanical and electrical components. Each electrical and / or mechanical component may have independent or different operating limitations, such as current, voltage, power, and / or temperature limits, than other components. Furthermore, known wind turbines are often designed and / or assembled with predefined nominal power limits. To operate within such power rating limits, electrical and / or mechanical components can be operated with large margins for operating limitations. Such operation can lead to inefficient operation of the wind turbine, and a power generating capacity of the wind turbine can be underutilized.

When a plurality of wind turbines are arranged in a wind farm, the reactive power generated by the individual wind turbines may be different.In particular, an increasing size of the wind farms leads to an increase in the surface of the wind farm, so that the difference in reactive power production, for example because of the difference in topology, also increases. Since an adjustable power factor (PF: power factor) is desired, such as a power factor equal to one (PF = 1), the control of a large number of wind turbines with identical or nearly identical commands to compensate for power reactive is not efficient. The larger the wind farm, the larger the area for the installation of individual wind turbines. Therefore, long electrical connections between individual wind turbines and an electrical bus bar to collect the energy provided by individual wind turbines is a problem. Therefore, efficient and cost-effective energy control is desired for wind turbines arranged in a wind farm.

Document DE 10 2004 048 341 refers to a wind farm with at least two turbines that are connected via connection lines to a main line, a coupling point connecting the main line with a power transmission network, and a master of the park.

DE 102009 030725 refers to a wind farm having a transfer point at which electrical values are measured. A master regulator provides a lower level of control than a plurality of sub-master regulators.

Document EP 1512 869 relates to voltage control in a wind farm. A measured reactive power is compared to a Q command at the operator or park level to determine a rotor current command.

The present invention is defined by the appended claims.

Various aspects, advantages, and features of the present invention are apparent from the dependent claims, description, and accompanying drawings, in which:

Figure 1 is a perspective view of a portion of an example wind turbine;

Figure 2 is a schematic view of an example electrical and control system suitable for use with the wind turbine shown in Figure 1;

Figure 3 is a schematic circuit diagram of a connection of different substations with a power supply network;

Figure 4 is a detailed diagram showing a configuration for a control scheme in a wind farm that includes three different sub-networks, according to a typical embodiment;

Figure 5 is a detailed diagram of a wind farm having three individual sub-networks, in which each sub-network includes an associated sub-network controller and a sub-network measurement device, according to another typical embodiment ;

Figure 6 is a detailed diagram of a wind farm with three individual sub-networks, in which primary and secondary controllers are provided in each sub-network, according to another typical embodiment;

Figure 7 is a flow chart illustrating a wind farm control procedure according to a typical embodiment; Y

Figure 8 is a flow chart illustrating a wind farm control procedure according to another typical embodiment.

Reference will now be made in detail to the various embodiments, one or more examples of which are illustrated in each Figure. Each example is provided by way of explanation and is not intended to be a limitation. For example, features illustrated or described as part of one embodiment may be used in or in conjunction with other embodiments to obtain additional embodiments. This disclosure is intended to include such modifications and variations.

The embodiments described in this document include a reactive power controller for a wind farm having a wind farm network that includes at least two sub-networks electrically connected to each other. The reactive power controller includes a determining device, such as a network measurement device, that is designed to measure a reactive power component of the electrical energy generated by at least one wind turbine in the sub-network. Furthermore, the reactive power controller includes a wind farm controller for controlling a power generation in at least one sub-grid based on the measured reactive power component. In this way, the reactive power component can be controlled with respect to at least one other sub-network.

In this document, the term "wind farm network" is intended to be representative of an electrical network for an electrical connection of devices used in a wind farm. As used herein, the term "sub-network" is intended to be representative of an electrical network provided for an electrical connection of a specific number of wind turbines in a wind farm, such as a group or series of wind turbines. that can be connected to the same power output cable, or to a virtual group of wind turbines that are controlled. Such a group can also be thought of as a "logic group" or a "virtual group" of individual wind turbines. As used herein, the term "wind farm topology" is intended to be representative of a specific topographical arrangement of wind turbines, for example an arrangement in sub-networks or series. As used herein, the term "blade" is intended to be representative of any device that provides a reactive force when in motion relative to a surrounding fluid. As used herein, the term "wind turbine" is intended to be representative of any device that generates rotational energy from wind energy and, more specifically, that converts kinetic energy from wind to mechanical energy. As used herein, the term "wind generator" is intended to be representative of any wind turbine that generates electrical energy from rotating energy generated from wind energy and, more specifically, converts converted mechanical energy to starting from kinetic energy of the wind into electrical energy. As used herein, the term "power factor" is intended to be representative of a cosine of an angle 9 so that cos (9) is a ratio of an effective power P and an absolute value of the complex power | S |.

Figure 1 is a perspective view of a portion of an example wind turbine 100. Wind turbine 100 includes a nacelle 102 that houses a generator (not shown in Figure 1). Gondola 102 it is mounted on a tower 104 (a portion of tower 104 is shown in Figure 1). Tower 104 can be of any suitable height that facilitates operation of wind turbine 100 as described herein. Wind turbine 100 also includes a rotor 106 that includes three blades 108 coupled to a rotating hub 110. Alternatively, wind turbine 100 includes any number of blades 108 that facilitate operation of wind turbine 100 as described herein. In the exemplary embodiment, wind turbine 100 includes a gearbox (not shown in Figure 1) operatively coupled with rotor 106 and a generator (not shown in Figure 1).

Figure 2 is a schematic view of an example electrical and control system 200 that can be used with wind turbine 100. Rotor 106 includes blades 108 coupled to a hub 110. Rotor 106 also includes a low speed shaft 112 rotatably coupled to the hub 110. The low speed shaft 112 is coupled with a gearbox 114 that is configured to increase the rotational speed of the low speed shaft 112 and transfer that speed to a high speed shaft 116. In In the exemplary embodiment, multiplier 114 has a lift or boost ratio of approximately 70: 1. For example, low-speed shaft 112 rotating at approximately 20 revolutions per minute (rpm) coupled with gearbox 114 with a lift or boost ratio of approximately 70: 1 generates a high-speed shaft 116 speed equal to approximately 1400. rpm. Alternatively, gearbox 114 has any suitable lift or increment ratio that facilitates operation of wind turbine 100 as described herein. As a further alternative, the wind turbine 100 includes a direct drive generator that is rotatably coupled to the rotor 106 without involving any multiplier.

High speed shaft 116 is rotatably coupled to generator 118. In the exemplary embodiment, generator 118 is a three-phase wound rotor induction (DFIG) (asynchronous) generator that includes a generator stator. 120 magnetically coupled to a generator rotor 122. In an alternative embodiment, the generator rotor 122 includes a plurality of permanent magnets in place of the rotor coils.

The electrical and control system 200 includes a turbine controller 202. The turbine controller 202 includes at least one processor and memory, at least one processor input channel, at least one processor output channel, and may include the minus one computing device (none is shown in Figure 2). As used in this document, the term computing device is not limited to integrated circuits that are referred to in the art as computing devices, but generally refers to a processor, a micro-controller, a micro-computing device, a logic controller. Programmable Logic Controller (PLC), an application-specific integrated circuit, and other programmable circuits (neither shown in Figure 2), and these terms are used interchangeably throughout this document. In the exemplary embodiment, the memory may include, but is not limited to, a computer-readable medium, such as a random access memory (RAM) (not shown in Figure 2). . Alternatively, you can also use one or more storage devices, such as a floppy disk, a compact disc read only memory (CD-ROM), a magneto-optical disk (MOD: magneto optical disk), and / or a digital versatile disc (DVD) (neither shown in Figure 2). Also, in the example embodiment, additional input channels (not shown in Figure 2) may be, but are not limited to, computer peripherals associated with an operator interface such as a mouse and keyboard (which not shown in Figure 2). Additionally, in the example embodiment, additional output channels may include, but are not limited to, an operator interface monitor (not shown in Figure 2).

The processors for a turbine controller 202 process information transmitted by a plurality of electrical and electronic devices that may include, but are not limited to, voltage and current transducers. RAM memory and / or storage devices store and transfer information and instructions for execution by the processor. RAM and / or storage devices can also be used to store and provide temporary variables, static (ie, non-changing) information and instructions, or other intermediate information to the processors during the execution of the instructions by the processors. The instructions that are executed include, but are not limited to, resident conversion and / or comparison algorithms. The execution of instruction sequences is not limited to any specific combination of hardware circuits and software instructions.

Generator stator 120 is electrically coupled with a stator timing switch 206 via a stator bus 208. In an exemplary embodiment, to facilitate configuration of the DFIG generator, generator rotor 122 is electrically coupled with a bidirectional power conversion unit 210 through a rotor bus 212. Alternatively, the generator rotor 122 is electrically coupled to the rotor bus 212 through any other device that facilitates the operation of the electrical and control system 200 as described herein. As another alternative, the electrical and control system 200 is configured as a full power conversion system (not shown) that includes a full power conversion unit (not shown in Figure 2) similar in design and operation to the power conversion unit 210 and electrically coupled with the generator stator 120. The full power conversion unit facilitates the conduction of electrical power between generator stator 120 and an electrical power transmission and distribution network (not shown). In the exemplary embodiment, the stator bus 208 transmits three-phase power from the generator stator 120 to the stator timing switch 206. The rotor bus 212 transmits three-phase power from the generator rotor 122 to the conversion unit. 210. In the example embodiment, the stator timing switch 206 is electrically coupled to a main transformer circuit breaker 214 via a system bus 216. In an alternate embodiment, one is used or more fuses (not shown) in place of the main transformer circuit breaker 214. In another embodiment, neither fuses nor the main transformer circuit breaker 214 are used.

The power conversion unit 210 includes a rotor filter 218 that is electrically coupled to the generator rotor 122 through the rotor bus 212. A rotor filter bus 219 electrically couples the rotor filter 218 with a power converter. on the rotor side 220, and the power converter on the rotor side 220 is electrically coupled with a power converter on the line side 222. The power converter on the rotor side 220 and the power converter on the 222 side of line are power converter bridges that include power semiconductors (not shown). In the example embodiment, the power converter on the rotor side 220 and the power converter on the line side 222 are configured in a three-phase pulse width modulation (PWM) configuration that includes insulated gate bipolar transistor (IGBT) switching devices (not shown in Figure 2) that operate as known in the art. Alternatively, the rotor-side power converter 220 and the line-side power converter 222 have any configuration that uses any switching device that facilitates the operation of the electrical and control system 200 as described herein. . The power conversion unit 210 is coupled in electronic data communication with the turbine controller 202 to control the operation of the power converter on the rotor side 220 and the power converter on the line side 222.

In the exemplary embodiment, a line-side power converter bus 223 electrically couples the line-side power converter 222 with a line filter 224. Also, a line bus 225 electrically couples the line filter 224 with a line contactor 226. In addition, the line contactor 226 is electrically coupled with a conversion circuit breaker 228 through a conversion circuit breaker bus 230. In addition, the conversion circuit breaker 228 is electrically coupled to main transformer circuit breaker 214 via system bus 216 and a link bus 232. Alternatively, line filter 224 is electrically coupled to system bus 216 directly via link bus 232 and includes any suitable protection scheme (not shown) configured to account for the removal of the line contactor 226 and the circuit breaker of the circuit breaker. version 228 with respect to the electrical and control system 200. The main transformer circuit breaker 214 is electrically coupled with a main electrical power transformer 234 via a bus on the generator side 236. The main transformer 234 is electrically coupled with a network circuit breaker 238 through a bus on the side of the circuit breaker 240. The network circuit breaker 238 is connected to the electrical power transmission and distribution network through a network bus 242. In In an alternative embodiment, the main transformer 234 is electrically coupled with one or more fuses (not shown), rather than with the network circuit breaker 238, across the bus on the side of the breaker 240. In In another embodiment, neither fuses nor the network circuit breaker 238 are used, but the main transformer 234 is coupled with the transmission and distribution network of ene Electrical power via the bus on the circuit breaker 240 side and the network bus 242.

In the exemplary embodiment, the rotor-side power converter 220 is coupled in electrical communication with the line-side power converter 222 via a single DC link. ) 244. Alternatively, the rotor-side power converter 220 and the line-side power converter 222 are electrically coupled via separate, individual DC links (not shown in Figure 2). DC link 244 includes positive rail 246, negative rail 248, and at least one capacitor 250 coupled between positive rail 246 and negative rail 248. Alternatively, capacitor 250 includes one or more capacitors configured in series and / or in parallel between positive rail 246 and negative rail 248.

Turbine controller 202 is configured to receive a plurality of voltage and electrical current measurement signals from a first set of voltage and electrical current sensors 252. Additionally, turbine controller 202 is configured to monitor and control the minus some of the operational variables associated with wind turbine 100. In the example embodiment, each of the three voltage and electrical current sensors 252 is electrically coupled to each of the three phases of the network bus 242 Alternatively, the voltage and electrical current sensors 252 are electrically coupled to the system bus 216. As a further alternative, the voltage and electrical current sensors 252 are electrically coupled to any part of the electrical and control system 200 that facilitates the operation of the electrical and control system 200 as described herein. As a further alternative, the turbine controller 202 is configured to receive any number of voltage and electrical current measurement signals from any number of voltage and electrical current sensors 252 including, but not limited to, a voltage and electrical current measurement signal from a transducer .

As shown in Figure 2, the electrical and control system 200 also includes a converter controller 262 that is configured to receive a plurality of voltage and electrical current measurement signals. For example, in one configuration, converter controller 262 receives voltage and electrical current measurement signals from a second set of voltage and electrical current sensors 254 coupled in electronic data communication with the stator bus 208. The converter controller 262 receives a third set of voltage and electric current measurement signals from a third set of voltage and electric current sensors 256 coupled in electronic data communication with rotor bus 212. Converter controller 262 it also receives a fourth set of voltage and electric current measurement signals from a fourth set of voltage and electric current sensors 264 coupled in electronic data communication with the conversion circuit breaker bus 230. The second set of voltage and electrical current sensors 254 is substantially similar to the first set set of voltage and electric current sensors 252, and the fourth set of voltage and electric current sensors 264 is substantially similar to the third set of voltage and electric current sensors 256. The converter controller 262 is substantially similar to the controller turbine controller 202 and is coupled in electronic data communication with turbine controller 202. Additionally, in the exemplary embodiment, converter controller 262 is physically integrated into power conversion unit 210. Alternatively, the power controller Converter 262 has any configuration that facilitates operation of the electrical and control system 200 as described herein.

During operation, the wind impacts the blades 108 and the blades 108 transform the wind energy into a mechanical torque that rotatably drives the low speed shaft 112 through the bushing 110. The low speed shaft 112 drives the multiplier 114 which subsequently increases the low speed of rotation of the low speed shaft 112 to drive the high speed shaft 116 at a higher speed of rotation. The high-speed shaft 116 rotationally drives the generator rotor 122. The generator rotor 122 induces a rotating magnetic field and a voltage is induced within the generator stator 120 that is magnetically coupled with the generator rotor 122. The generator 118 converts rotational mechanical energy into a sinusoidal, three-phase alternating current (AC) electrical energy signal in generator stator 120. The associated electrical energy is transmitted to main transformer 234 via stator bus 208 , the stator timing switch 206, the system bus 216, the main transformer circuit breaker 214 and the bus on the generator side 236. The main transformer 234 increases the amplitude of the voltage of the electrical power and the electrical power The transformed transformation is further transmitted to a network via the bus on the side of circuit breaker 240, network circuit breaker 238, and l network bus 242.

In the exemplary embodiment, a second electrical power transmission path is provided. Sinusoidal three-phase alternating current electrical power is generated within generator rotor 122 and transmitted to power conversion unit 210 via rotor bus 212.

Within the power conversion unit 210, the electrical power is transmitted to the rotor filter 218 and the electrical power is modified for the rate of change of the PWM signals associated with the power converter on the rotor side 220. The Power converter on the rotor side 220 acts as a rectifier and rectifies sinusoidal and three-phase alternating current power into a DC power. DC power is transmitted to DC link 244. Capacitor 250 facilitates mitigation of voltage amplitude variations on DC link 244 by facilitating mitigation of a DC ripple associated with AC rectification.

The DC power is subsequently transmitted from the DC link 244 to the power converter on the line side 222 and the power converter on the line side 222 acts as an inverter configured to convert the DC electrical power from the DC link 244 in sinusoidal and three-phase AC electrical power with predetermined voltages, currents and frequencies. This conversion is monitored and controlled through the converter controller 262. The converted AC power is transmitted from the line-side power converter 222 to the system bus 216 via the power-side converter bus. line 223 and line bus 225, line contactor 226, conversion circuit breaker bus 230, conversion circuit breaker 228 and connection bus 232. Line filter 224 compensates or adjusts currents harmonics in the electrical power transmitted from the line-side power converter 222. The stator timing switch 206 is configured to close to facilitate connection of the three-phase power from the generator stator 120 with the three-phase power from the energy conversion unit 210.

The conversion circuit breaker 228, the main transformer circuit breaker 214, and the mains circuit breaker 238 are configured to disconnect the corresponding buses, for example, when excessive current flow can damage electrical system components and of control 200. Additional protection components are also provided including line contactor 226, which can be controlled to form a disconnect by opening a switch (not shown in Figure 2) corresponding to each line of line bus 225.

The power conversion unit 210 compensates or adjusts the frequency of the three-phase power from the generator rotor 122 for changes, for example, in the wind speed at the hub 110 and blades 108. Thus, thereby, the mechanical and electrical frequencies of the rotor are decoupled from the stator frequency.

Under some conditions, the bi-directional characteristics of the power conversion unit 210, and in particular the bi-directional characteristics of the power converter on the rotor side 220 and of the power converter on the line side 222, facilitate feedback from at the same time. less part of the electrical energy generated in the generator rotor 122. More specifically, electrical energy is transmitted from the system bus 216 to the connection bus 232 and subsequently through the conversion circuit breaker 228 and from the Conversion circuit breaker bus 230 to power conversion unit 210. Within power conversion unit 210, electrical power is transmitted through line contactor 226, line bus 225, and converter bus. of power on the line 223 side to the power converter on the 222 line side. The power converter on the 222 line side acts as a rectifier generator and rectifies sinusoidal and three-phase alternating current energy in the form of DC energy. The DC power is transmitted to the DC link 244. The capacitor 250 facilitates the mitigation of voltage amplitude variations on the DC link 244 by facilitating the mitigation of a DC ripple sometimes associated with three-phase AC rectification.

The DC power is subsequently transmitted from the DC link 244 to the rotor-side power converter 220 and the rotor-side power converter 220 acts as an inverter configured to convert the DC electrical power transmitted from the DC link 244 in sinusoidal and three-phase AC electrical power with predetermined voltages, currents and frequencies. This conversion is monitored and controlled by the converter controller 262. The converted AC power is transmitted from the rotor-side power converter 220 to the rotor filter 218 via the rotor filter bus 219 and is subsequently transmitted to generator rotor 122 via rotor bus 212, thereby facilitating subsynchronous operation.

The power conversion unit 210 is configured to receive control signals from the turbine controller 202. The control signals are based on sensed conditions or operating characteristics of the wind turbine 100 and the electrical and control system 200. Control signals are received by the turbine controller 202 and are used to control the operation of the power conversion unit 210. The electrical and control system 200 may use feedback from one or more sensors to control the conversion unit. power supply 210 through converter controller 262, including, for example, conversion circuit breaker bus 230, stator bus and rotor bus voltage or current feedbacks through second set of voltage sensors and electric current 254, the third set of voltage and electric current sensors 256, and the fourth set of sin 264 voltage and electrical current sources. Using this feedback information and, for example, switching control signals, stator timing switch control signals, and circuit breaker control (actuation) signals can be generated in any known manner. system circuit. For example, for a mains voltage transient with predetermined characteristics, the converter controller 262 will suspend, at least substantially temporarily, that the IGBT transistors conduct within the power converter on the line side 222. Said suspension of the operation of the Line side power converter 222 will substantially mitigate the conduction of electrical power through power conversion unit 210 down to about zero.

Figure 3 is a schematic diagram illustrating a connection scheme for individual substations 606, 607, and 608 with a common power line 612. Substations 606, 607, and 608 may form associated sub-networks, in which each subnet includes an associated subnet transformer (as illustrated in Figures 4 and 5). Reference numeral 605 indicates a reactive power compensation region. A first substation 606, a second substation 607, and a third substation 608 are provided. The power S supplied by the individual substations includes, respectively, effective power components P and reactive power components Q. It is indicated in this case that, although the determination of reactive power components is described in this document, the effective power components P and / or power S can be determined so that the reactive power components can be evaluated using S And p.

In order to reduce unwanted components of reactive power Q, or to control reactive power so as to obtain a desired reactive power value and / or a desired power factor, a first reactive power compensation 610 may be provided by transferring reactive power Q between substation 608 and substation 607. In addition, a second reactive power compensation 611 may be provided by a handoff from substation 608 to substation. station 606 (as shown by arrows 610, 611 in Figure 3). It is noted in this case that, as used herein, the term "reactive power compensation" is intended to be representative of a reactive power control that can result in a total or partial compensation of reactive power, for For example, according to requirements of an external power supply network and / or other loads connected to the wind farm network.

As an example, each of the three substations 606, 607 and 608 can include 20 wind turbines. Furthermore, according to the present example, a cable load load in substation 606 is equal to 10 MVAr capacitive, a cable load load in substation 607 is equal to 20 MVAr capacitive, and a load load of cable in sub-station 608 is equal to 30 capacitive MVAr. Therefore, according to the example described in this case, the sum of the cable load loads amounts to 10 MVAr 20 MVAr 30 MVAr = 60 MVAr. A wind farm management system without individual sub-grid control will provide identical or nearly identical commands for each wind turbine. These commands are estimated as follows: 60 MVAr / 60 = 1.0 MVAr inductive. Taking into account that individual sub-networks have different lengths and that the number of wind turbines connected to a sub-network may be different, the reactive power Q generated by the reactance and inductance of cable and transformers may be different. In the case of a park voltage, a volt-ampere reactive (VAR: volt amps reactive) or power factor (PF: power-factor) regulator regulates a park setpoint and adjusts all wind turbines using the same VAR command, the reactive power Q generated in the sub-grids will be different. Situations may arise where in one sub-network the reactive power Q may be positive, while in another sub-network the reactive power Q may be negative. Then, a compensatory reactive power flow can occur between the sub-networks that can stress one or more of the sub-network transformers and / or the busbar. As a result, inefficient operation of the entire wind farm can occur.

The electrical power supplied by the individual substations is provided to associated electrical transformers, for example, a first high-voltage transformer 602, a second high-voltage transformer 603, and a third high-voltage transformer 604. Each of these transformers can provide the transformation from 110 kV to 400 kV, that is, from the high voltage region to the ultra high voltage region (from 3 x 110 kV to 3 x 400 kV).

The first reactive power offset 610 may be provided from substation 608 to substation 607. Furthermore, the second reactive power offset 611 may be provided from substation 608 to substation 606. From this Thus, substation 608 includes turbines that produce less reactive power Q than requested through the power line, while substations 606 and 607 include wind turbines that produce more reactive power Q than requested through the line. electrical. In this case, unwanted compensation of reactive power may occur across the 110 kV bus bar. It is observed in this case that the electrical connection lines within the wind farm normally contribute to the capacitive part of the reactive power, while at least one wind turbine connected to an associated sub-network normally contributes to the inductive part of the reactive power. . The capacitive part of the reactive power is more or less constant due to the fixed wiring and therefore the unaltered electrical connection lines during the operation of the at least one wind turbine. However, the inductive part of the reactive power can be adjusted in an individual wind turbine such that the one or more reactive power offsets 610, 611 mentioned above can be provided. The control of inductive parts of the reactive power in individual wind turbines therefore makes it possible to compensate for the capacitive parts of the reactive power resulting from the electrical connection lines within the wind farm. Larger wind farms occupy a larger area for the installation of wind turbines. This fact results in long power transfer cables to collect energy from individual wind turbines. In order to reduce the cost of cabling, the number of wind turbines connected to a cable is limited. All sub-network cables are connected to a common bus bar in the sub-station. In this case, the reactive power compensation flow could appear and increase the losses of the entire wind farm.

According to a typical embodiment of the present invention, the individual substations 606, 607, and 608 can be controlled in such a way that the reactive power of the substations is individually compensated. In this case no compensation is made via the 110 kV bus bar. In this way, each power line to individual substations 606, 607, and 608 is separately compensated to provide a desired power factor PF, eg, a power factor PF equal to one (PF = 1). Thus, the cosine of the angle 9 between the effective power P and the output power | S | It can be set to cos (9) = 1 with cos (9) = P / | S |. Therefore, the relation PF = 1 corresponds to 9 = 0 ° or Q = 0.

Figure 4 is a schematic diagram showing a configuration of a wind farm according to a typical embodiment. The wind farm topology illustrated in Figure 4 includes an arrangement of wind turbines, for example, an arrangement of wind turbines in sub-grids or series. Said topology arrangement can be stored in a memory so that the components Reactive power and / or power factors resulting from, or influenced by, the topology of a specific sub-network or of a series of sub-networks can be evaluated based on the known and stored topology. A wind farm network is connected to a power supply network 900 and includes at least two sub-networks 300, 400, 500 and a collector part 905. The at least two wind turbines are connected to each of the sub-networks 300, 400, 500, in which the at least two sub-networks 300, 400, 500 are connected to the collector part 905 and in which the collector part 905 establishes the connection with the supply network 900. A reactive power controller is operatively connected to the wind farm network, wherein the reactive power controller includes a determining device for determining an actual reactive power value in the collector portion 905 and a wind farm controller 800 operatively connected to the determining device 700 to control at least two of said wind turbines based on the determined real reactive power value, so that a desired reactive power value is reached.

Thus, the wind farm shown in Figure 4 includes three sub-networks, that is, a first sub-network 300, a second sub-network 400 and a third sub-network 500. It is observed in this case, Although not shown in the drawings, that more than three sub-networks or less than three sub-networks can be provided. The collector portion 905 (dashed line in Figure 4) may include a bus bar 600, a substation transformer 601, and a determining device 700, and may represent a connection to the power supply network 900 through a Grid regulation point 707. According to a typical embodiment that can be combined with other embodiments described in this document, a real reactive power value Q can be measured at grid regulation point 707. From this Thus, a desired output power factor - or a desired reactive power value at the output - from the wind farm network can be provided to a power supply network connected to the wind farm network in the collector part 905 - and, in turn, a desired reactive power value of the wind farm network. In other words, to achieve a desired reactive power value at least two of said wind turbines can be controlled based on the determined actual reactive power value. Furthermore, determining a real power value of the electrical energy output generated by the wind farm network, towards an external power supply network, may include evaluating or measuring reactive power components in one or all of the sub-networks in based on the topology of at least one subnet. It is observed in this case that a desired reactive power value and / or a desired PF power factor can be set on the bus bar 600. The adjusted PF power factor at a tap point 706 (dashed line in Figure 4) it is a basis for billing the electricity generated. Therefore, a power factor PF = 1 at the busbar can be advantageous even if the power factor at grid regulation point 707 is less than 1. In other words, it may be desirable for the wind farm operator to provide a power factor PF close to one at a location (eg, at bus bar 600 in Figure 4) within the wind farm network where this power factor represents the basis for billing. Using the procedure according to one or more typical embodiments described in this document, it is therefore possible to adjust this power factor based on sub-network measurements.

Each sub-network 300, 400, 500 includes at least two wind turbines 301 - 303, 401, 402, and 501 - 504. Electric power is generated with at least two of said wind turbines and is supplied to the sub-network with the one to which the at least two wind turbines are connected. It is observed in this case that the topology can influence the reactive power components in a sub-network. Thus, reactive power in one sub-network may be different from reactive power in another sub-network, for example, due to different lengths of cables, different number of wind turbines connected to a sub-network, etc. Thus, topology is a factor that can be considered when controlling reactive power components. In the embodiment shown in Figure 4, the first subnet 300 includes three wind turbines 301, 302, 303, the second subnet 400 includes two wind turbines 401 and 402, and the third subnet 500 It includes four wind turbines 501, 502, 503 and 504. The actual reactive power value can be determined in the collector part 905.

Each individual wind turbine 301-303, 401-402, 501-503 includes an associated wind turbine controller. Furthermore, for each sub-network 300, 400 and 500 an associated sub-network transformer may be provided to connect the respective sub-network 300, 400 and 500 to the common bus bar 600. Said sub-network transformer may be adapted to transfer electrical energy in a range of 150 MW to 250 MW. The common bus bar is used to collect the electrical energy generated by the individual wind turbines. The resulting Spark electrical energy is transferred to sub-station transformer 601, which transforms Spark electrical energy from a high-voltage HV region to an ultra-high-voltage region (UHV region). The sub-station transformer 601 can be considered as a main transformer in the wind farm. On the ultra-high voltage side of the sub-station transformer 601, a supply network 900 can be connected. In this way, the wind farm network electrically connected to at least two sub-networks can be connected to the supply network. of energy and the generated power can be transferred from the wind farm that has at least two sub-grids to the energy supply network. A network regulation point is indicated by reference numeral 707. At the network regulation point 707, voltages and currents can be measured by a network measurement device 700, so that reactive power control is possible. .

According to a typical embodiment that can be combined with other embodiments described herein, the network measurement device 700 includes a voltage sensor 704 and a current sensor 705, so that power components are detected. effective P and reactive power components Q on the secondary side of the substation transformer 601. A measurement signal 903 produced by the grid measurement device 700 is used to control a wind farm controller 800 connected with the measurement device. network 700. In addition, the wind farm controller 800 is connected to a network input device 901 to supply a desired control state for the individual wind turbines and to a man-machine interface 902 to supply user commands. A wind farm control signal 804 is outputted by the wind farm controller 800 and can be used to control individual wind turbines through their associated wind turbine controllers. In order to provide wind turbine control, wind park controller 800 is connected to individual wind turbines 301-303; 401-402; 501-503 through a data communication device 904 such as a communication line (dashed lines in Figure 4). Communication line 904 is used to communicate data signals between wind farm controller 800 and individual wind turbines / wind turbine controllers.

According to another typical embodiment that can be combined with other embodiments described in this document, the data communication device can serve to communicate data signals between the wind farm controller and at least one wind turbine, in the that the data communication device can be selected from a group consisting of a local area network, a wireless LAN, the Internet, an optical waveguide, and any combination thereof.

The network measurement device 700 for measuring a Qpark reactive power component of the Spark electrical energy generated by wind turbines may include at least one sensor selected from the group consisting of a voltage sensor 704, a current sensor 705, a power meter, a VAR sensor, and any combination thereof. Using the network measurement device 700 according to a typical embodiment that is described in this document with respect to Figure 4, the reactive power component Qpark contained in the generated power Spark (which includes components of effective power and reactive power).

Each sub-network 300, 400 and 500 includes a group of wind turbines 301-303; 401-402; 501-503 that are connected to the same power output cable, so that a group of wind turbines can be controlled with respect to their power output. The output power in the individual sub-network 300, 400 and 500 is according to the following equations (1), (2) and (3), respectively:

£, = P, jQ, (O

S2 = P 2 jQ 2 (2)

Sj = P? jQ i (3)

In this way, the resulting amount of Spark electrical energy generated by the wind turbines arranged within the wind farm is evaluated using the complex energy formulation defined by equations (1), (2) and (3) above:

Spark = Yes S2 Yes (4)

Thus, the power generated by the Spark wind farm includes components of effective power Ppark and components of reactive power Qpark, as indicated in the following equation (5):

Spark Ppark ~ ^. | Qpark (5)

Using equation (5) above, the sum of reactive power components Qpark within the wind farm can be determined using the following equation (6):

Qpark = Q l Q 2 Q? (6)

It is observed in this case that the individual reactive power components provided by the individual sub-networks 300, 400 and 500 can be expressed as the sum of the respective reactive power components established by a Q command and the respective reactive power components at cause of a cable transmission Q_cabletrans. Thus, the following equations (7) to (8) can be used:

Q lco m m an d Q lcablctrans (7)

2 cabletrans (8)

3 cahletrans (9)

As the individual sub-networks 300, 400 and 500 are different from each other, for example, with respect to topology, the number of connected wind turbines, the length of the cables, the installation area, etc., the components of reactive power due to cable transmission Q_cabletrans are also different from each other:

Therefore, if the reactive power components established by a Q command correspond to each other, as indicated in the following equation (11), all the wind turbines connected to the respective sub-grids 300, 400 and 500 would be controlled accordingly. the same way.

Q ^{! command Q 2 command Q] co land (11)}

Then, Qpark is established according to the following equation (12):

IF: Q2 <0

AND: Qi> 0; What > 0 (12)

TF1EN: Q2 compensated by Qi, Q „r

Qpock = IQil IQ * I - IQ2I

However, according to a typical embodiment, individual control of the reactive power components is provided. The individual reactive power components provided by the cable transmission are calculated and a Qpark command is generated by a control device.

In this way, the reactive power components can be controlled or set by the Q_command commands that are provided individually for the three sub-networks 300, 400 and 500. In addition, the reactive power components can be overridden in such a way that, by For example, the reactive power of at least two sub-networks can be offset against each other. In this way, the Q_command command can be weighted according to an effective cable transmission in the respective sub-network and can be calculated as indicated in the following equation (13) for the first sub-network 300, in the following equation (14) for the second subnet 400 and in the following equation (15) for the third subnet 500:

It is noted in this case that the weighting according to the above equations can be provided as a dynamic weighting, for example, a weighting when one or more Q_cabletrans cable transmissions change. In this way, the reactive power components in the individual sub-networks 300, 400 and 500 can be set, and a setting of a desired reactive power value of the wind farm network can be achieved.

In addition, complete or partial compensation Qcomp of reactive power components Q is provided near a tap point 706 on busbar 600. Thus, virtual groups or series or sub-grids can be used to control reactive power Q in these groups without measuring a reactive power in each group. In this way, a segmented control of reactive power can be provided. As used herein, the term "reactive power value" is intended to be representative of a reactive power value that is provided to a power supply network connected to the wind farm network. It is noted in this document, although not shown in the drawings, that more than three sub-networks or less than three sub-networks can be provided.

Thus, a reactive power controller for a wind farm having at least two sub-grids includes a grid determining device 700, such as the grid measurement device for measuring a reactive power component Q of electrical energy. generated by the respective wind turbines, and the wind farm controller 800 to control the power generation in at least one sub-grid based on the measured reactive power component Q, so that the reactive power component Q is controlled with respect to to at least one other subnet.

It is observed in this case that each sub-network 300, 400 and 500 includes two wind turbines or more than two wind turbines. Wind farm controller 800 may include a CPU that cooperates with network metering device 700.

Figure 5 is a schematic diagram of a wind farm configuration according to another typical embodiment. It is noted in this case that the components that have been described with respect to Figure 4 are not described in this case to avoid redundant description. A wind farm network is provided connected to supply network 900 and includes at least two sub-networks 300, 400, 500 and collector part 905. At least one wind turbine is connected to each sub-network 300, 400, 500 , in which the at least two sub-networks 300, 400, 500 are connected to the collector part 905 and in which the collector part 905 establishes the connection with the supply network 900.

As indicated in Figure 5, each sub-network 300, 400 and 500 includes a respective sub-network measurement device, that is, the first sub-network 300 includes a first sub-network measurement device 701, the The second sub-network 400 includes a second sub-network measurement device 702, and the third sub-network 500 includes a third sub-network measurement device 703. In this way, the reactive power components Q can be measured directly. in the power lines of the respective sub-networks 300, 400 and 500. Thus, according to the typical embodiment shown in Figure 5, a reactive power component can be determined in each sub-network 300, 400, 500. In this way, at least two of said wind turbines are controlled based on the determined reactive power components, in such a way that a desired reactive power value is reached. The desired actual power value is provided on the collector portion 905.

In addition to that, or alternatively, individual sub-network drivers may be provided. As shown in Figure 5, the first subnet 300 includes a first subnet controller 801 connected to the first subnet measurement device 701, the second subnet 400 includes a second subnet controller 802 connected with the second subnet metering device 702, and the third subnet 500 includes a third subnet controller 803 connected with the third subnet metering device 703. The subnet controllers 801 , 802 and 803 are connected to the individual wind turbine controllers through sub-network data communication devices such as communication lines (dashed lines in Figure 5), that is, the first sub-network controller 801 is connected to the wind turbine controllers 311, 312 and 313, the second sub-network controller 802 is connected to the wind turbine controllers 411 and 412, and the third sub-network controller 803 is connected to the turbine controllers wind 511, 512, 513 and 514. The individual sub-network controllers 801, 802 and 803 are respectively connected to the wind farm controller 800.

The collector part 905 (dashed line in Figure 5) includes the bus bar 600, the substation transformer 601 and the determining device 700, and may represent a connection to the supply network 900 through the regulation point of network 707. According to a typical embodiment that can be combined with other embodiments described in this document, the reactive power component Q can be measured at the network regulation point 707. Thus, in addition to or alternatively to the measurement of the reactive power components Q in the electrical lines of the respective sub-networks 300, 400 and 500 by means of the first sub-network measurement device 701, the second sub-network measurement device 702 and the third sub-network measurement device 703, respectively, the reactive power component Q can be measured at the network regulation point 707.

Thus, the wind farm controller 800 is used to control the individual sub-network controllers 801, 802, and 803 which in turn control the respective wind turbines in the associated sub-network 300, 400, and 500. Observed in In this case the current and voltage measurements provided by the sub-network measurement devices are performed on a secondary side of the respective sub-network transformers 321, 421 and 521. The sub-network transformers 321, 421 and 521 They are used to transform the energy generated by the individual sub-grids 300, 400 and 500 from the MV medium voltage range to the HV high voltage range. Therefore, voltage and current measurement is performed on the high voltage (HV) side of sub-grid transformers 321, 421, and 521.

One or more of the sub-network controllers 801, 802, and 803 to control power generation in at least one of the sub-networks 300, 400, and 500 based on a reactive power component Q measured by the respective switching device. Network metering 701, 702, and 703 are used to control the reactive power component Q with respect to at least one other sub-network. Thus, after generating energy power with at least one of said wind turbines and supplying the electrical energy generated to the sub-grid with which the at least one wind turbine is connected, a reactive power component can be determined in each sub-grid and can be controlled at least two of said wind turbines based on the determined reactive power components, so that a desired reactive power value is reached. The desired reactive power value can be provided on the collector portion 905.

It is noted in this case that the first sub-network measurement device 701 and / or the second sub-network measurement device 702 and / or the third sub-network measurement device 703 can include at least one sensor selected from between the group consisting of a voltage sensor, a current sensor, a power meter, and a VAR sensor, and any combination thereof. The data communication lines between individual wind turbines and the associated sub-network controller within a sub-network (dashed lines in Figure 5) can be replaced by other communication devices such as, for example, a network of local area, a wireless LAN, the Internet, an optical waveguide, and any combination thereof.

Figure 6 is a detailed diagram of a wind farm having three individual sub-networks, in which primary and secondary controllers are provided in each sub-network, according to another typical embodiment. It is noted in this case that the components that have been described with respect to Figures 4 and 5 are not described in this case to avoid redundant description. A wind farm network connected to the supply network 900 is provided and includes at least two sub-networks 300, 400, 500 and the collecting part 905. At least two wind turbines are connected to each sub-network 300, 400, 500 , in which the two sub-networks 300, 400, 500 are connected to the collector part 905 and in which the collector part 905 establishes the connection with the supply network 900.

Each sub-network 300, 400 and 500 includes a respective sub-network measurement device, that is, the first sub-network 300 includes a first sub-network measurement device 701, the second sub-network 400 includes a second sub-network measurement device 702, and the third sub-network 500 includes a third sub-network measurement device 703. Using these sub-network measurement devices, the reactive power components Q can be determined directly at the power lines of the respective sub-networks 300, 400 and 500. In this way, at least two of said wind turbines can be controlled based on the determined reactive power components, in such a way that a desired reactive power value is reached. . The desired actual power value can be provided on the collector portion 905.

In accordance with a typical embodiment that can be combined with other embodiments described herein, subnet controllers 801a, 802a, and 803a are provided on individual subnets 300, 400, 500. In the embodiment illustrated in Figure 6, a first sub-network controller 801a can act as the primary sub-network controller, while the second and third sub-network controller 802a, 803a can be provided as secondary subnet drivers. As shown in Figure 6, the first subnet 300 includes the first subnet controller 801a connected to the first subnet measurement device 701, the second subnet 400 includes the second subnet controller 802a connected with the second subnet metering device 702, and the third subnet 500 includes the third subnet controller 803a connected with the third subnet metering device 703. The subnet controllers 801a, 802a and 803a are connected to the individual wind turbine controllers through sub-network data communication devices such as communication lines (dashed lines in Figure 6), that is, the first sub-network controller 801a is connected to the wind turbine controllers 311, 312 and 313, the second sub-network controller 802a is connected to the wind turbine controllers 411 and 412, and the third sub-network controller 803a is connected to the wind turbine controllers 511 , 512, 513 and 514. Thus, the first subnet controller 801a that acts as the primary subnet controller and is operatively connected to the secondary subnet controllers 802a and 803a can be used to control the secondary sub-network controllers 802a and 803a which, in turn, can control the respective wind turbines in the associated sub-networks 400 and 500. Thus, the generation of power in at least one sub-network 300, 400, 500 based on the measured reactive power component Q can be provided such that the reactive power component Q is controlled with respect to at least one other sub-network. The generation of electrical energy with at least two of said wind turbines can be controlled and the generated electrical energy can be supplied to the sub-network with which the at least two wind turbines are connected, so that a component of reactive power in each sub-network. In this way, at least two of said wind turbines are controlled based on the determined reactive power component, so that a desired reactive power value is reached. The desired reactive power value is provided in the collector part 905. It is noted in this case that the first sub-network measurement device 701 and / or the second sub-network measurement device 702 and / or the third sub-network measurement device Subnet measurement 703 may include at least one sensor selected from the group consisting of a voltage sensor, a current sensor, a power meter, and a VAR sensor, and any combination thereof. The data communication lines between individual wind turbines and the associated sub-network controller 801a, 802a, 803a within a sub-network (dashed lines in Figure 6) can be replaced by other communication devices such as, but without I mimic a local area network, a wireless LAN, the Internet, an optical waveguide, and any combination thereof. According to another alternative embodiment that can be combined with other embodiments described herein, a measurement signal 903 and / or park network measurement signals generated by the determining device 700 can be used to control the primary subnetwork controller 801a connected to determining device 700 (dashed line in Figure 6). In addition, the primary sub-network controller 801a may be connected to a power supply input device 901 to supply a desired control state and / or power supply commands for individual wind turbines, and to a man-machine interface 902. to supply user commands. In this way, the first sub-network controller 801a acting as a primary sub-network controller can take over primary control of the wind farm shown in Figure 6.

Figure 7 is a flow chart illustrating a wind farm control procedure according to a typical embodiment. In a block 1000, the procedure is started. A wind farm network is provided connected to a power supply network 900 and including at least two sub-networks and a collector part. At least two wind turbines are connected to each sub-network, in which the at least two sub-networks are connected to the collector part and in which the collector part establishes the connection with the supply network 900 (block 1001). Then the electrical energy is generated with at least two of the wind turbines (block 1002). The electrical energy generated is supplied to the sub-network with which the at least two wind turbines are connected (block 1003). Then, at block 1004, an actual reactive power value is determined at the collector portion. In a block 1005, at least two of said wind turbines are controlled based on the determined real reactive power value, such that a desired reactive power value is reached. The procedure ends in a block 1006.

Determining the actual reactive power value of the generated electrical power S at block 1003 may include measuring a current and a voltage on the high voltage side of at least one sub-grid transformer 321, 421, 521. The component control procedure Reactive power Q (block 1004 of Figure 7) may include canceling the reactive power Q of at least two adjacent sub-networks 300, 400, 500.

Control power generation in at least one sub-network based on the measured reactive power component Q, so that the reactive power component Q adjusted in accordance with block 1004 may include data signal communication between the power controller. wind farm 800 and at least two wind turbines, between wind farm controller 800, at least one sub-grid controller 801, 802, 803 and individual wind turbines. Therefore, controlling power generation in at least one sub-network based on the measured reactive power component Q may include communicating data signals between a sub-network controller 801, 802, 803 associated with at least one sub-network 300, 400, 500 and at least two wind turbines of said sub-network 300, 400, 500.

The electric power transfer procedure from a wind farm that has at least two sub-networks and the reactive power controller for a wind farm arranged in at least two sub-networks according to typical embodiments described in the present document , provides a reduction of the compensating current flow through one or more transformers. In this way, for example, overheating of wind turbines due to excessive reactive power transfer can be avoided. Additionally, available wind turbine Q resources that do not overheat can be used to reduce Q components in overheated wind turbines. In addition to this, the electric power transfer procedure and the reactive power controller according to typical embodiments described in this document can help avoid paying fines for insufficient Q compensation at the point of interconnection (POI: point of interconnection).

Figure 8 is a flow chart illustrating a wind farm control procedure according to a further typical embodiment. At block 1100, the procedure starts. A wind farm network is provided connected to a power supply network 900 and including at least two sub-networks and a collector part. At least two wind turbines are connected to each sub-network, in which the at least two sub-networks are connected to the collector part and in which the collector part establishes the connection with the supply network 900 (block 1101). Then, electrical power is generated with at least two of the wind turbines (block 1102). The electrical energy generated is supplied to the sub-network with which the at least two wind turbines are reconnected (block 1103). Then, at block 1104, a reactive power component is determined in each sub-network. In a block 1105, at least two of said wind turbines are controlled based on the determined reactive power components, such that a desired reactive power value is reached. The procedure ends in a block 1106.

Examples of embodiments of systems and procedures for transferring electrical energy from a wind farm having at least two sub-grids to a power supply network have been described above in detail. The systems and procedures are not limited to the specific embodiments described herein, but the components of the systems and / or the steps of the procedures can be used independently and separately with respect to other components and / or steps described herein. For example, a reactive power controller for a wind farm arranged in at least two sub-grids is not limited to practice with only wind turbine systems as described in this document. Rather, the example embodiment can be implemented and used in connection with many other wind turbine applications.

Although specific features of various embodiments of the invention may be shown in some drawings and not others, this is for convenience only. In accordance with the principles of the invention, any feature of one drawing can be referenced and / or claimed in combination with any feature of any other drawing.

This written description uses examples to disclose the invention, including the preferred embodiment, and also to enable any person skilled in the art to practice the invention, including the manufacture and use of any devices or systems and the performance of any procedures. built-in. Although various specific embodiments have been disclosed above, those skilled in the art will recognize that the scope of the claims allows equally effective modifications. In particular, mutually non-exclusive features of the above-described embodiments can be combined with each other. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to fall within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal language of the claims.

Claims (12)

1. A reactive power controller to control a reactive power in a wind farm network connected to a power supply network and comprising at least two sub-networks (300, 40o, 500) and a collector part (905), in which at least two wind turbines (301, 401, 501) are connected to each sub-network of the at least two sub-networks, in which the at least two sub-networks are connected to the collector part (905) and in that the collecting part establishes the connection with the power supply network, the reactive power controller comprising: at least one sub-network measurement device (701, 702, 703) arranged in each sub-network, to measure a reactive power component in each sub-network (300, 400, 500); at least one sub-network controller (801, 802, 803) operatively connected to the at least one sub-network measurement device (701, 702, 703) to control said at least two wind turbines (301, 401, 501 ) connected to the sub-network based on the reactive power component measured in each sub-network (300, 400, 500) in such a way that a desired reactive power value is reached in each sub-network; wherein at least one sub-network controller (801. 802, 803) is connected to individual wind turbine controllers of wind turbines (301, 302, 303) connected to the sub-network; a determining device (700) for determining an actual reactive power value in the collecting portion (905); Y a wind farm controller (800) operatively connected to the determining device (700) to control at least one of the at least one sub-network controller (801, 802, 803) based on the actual reactive power value determined in the collector part (905), such that a desired reactive power value is reached in the collector part (905); and wherein each sub-network (300, 400, 500) includes an associated sub-network transformer (321, 421, 521) used to transform the energy generated by the individual sub-networks (300, 400, 500) of medium voltage to a high voltage range; and wherein the wind farm controller (800) is used to control individual sub-network controllers (801, 802, 803) that control respective wind turbines in the associated sub-network (300, 400, 500), and in the that current and voltage measurements are made by the sub-network measurement devices to measure reactive power components on each sub-network side of the respective sub-network transformers (321, 421, 521) and wherein the collector part (905) comprises a bus bar (600) and a tapping point (706) is provided between said at least two sub-networks (300, 400, 500) and said bus bar (600) and is provides complete or partial compensation (Qcomp) of reactive power components (Q) near tap point (706) on bus bar (600) by means of reactive power values reached in each sub-network. The reactive power controller according to any one of the preceding claims, further comprising a reactive power compensator to provide an output power factor close to one. The reactive power controller according to claim 2, wherein the output power factor close to one is provided on a bus bar (600). The reactive power controller according to any one of the preceding claims, wherein a plurality of wind turbines (401, 402) are connected to at least one sub-network (400). 5. The reactive power controller according to any one of the preceding claims, further comprising in at least one of said sub-networks (300, 400, 500): the high voltage at least one sub-network controller (801, 802, 803) to control the power generation in at least two wind turbines (301, 401, 501) based on the determined real reactive power value, in such a way that it is established a reactive power value with respect to at least one other sub-network (300, 400, 500). 6. The reactive power controller according to any one of the preceding claims, further comprising in at least one of said sub-networks (300, 400, 500): a sub-network measurement device (701, 702, 703) to measure a reactive power value of the electrical energy generated in at least one of said wind turbines (301, 401, 501) connected with at least one of said sub -networks (300, 400, 500). The reactive power controller according to any one of the preceding claims, wherein the device comprises at least one sensor (252, 254, 256, 264) selected from the group consisting of a voltage sensor, a voltage sensor current, a power meter, a volt-amp reactive sensor, VAR, and any combination thereof. The reactive power controller according to any one of the preceding claims, wherein the sub-network measurement device (701, 702, 703) comprises at least one sensor (252, 254, 256, 264) selected from among the group consisting of a voltage sensor, a current sensor, a power meter, a volt-amp reactive sensor, VAR, and any combination thereof. The reactive power controller according to any one of the preceding claims, further comprising at least one data communication device (904) for communicating data signals between the wind farm controller (800) and at least two wind turbines ( 301, 401, 501), wherein the data communication device (904) is selected from a group consisting of a local area network, a wireless LAN, the Internet, an optical waveguide, and any combination of the same. The reactive power controller according to any one of the preceding claims, further comprising at least one subnetwork data communication device for communicating data signals between at least one of said subnetwork controllers (801, 802 , 803) and at least two wind turbines (301, 401, 501) arranged in said sub-network (300, 400, 500), wherein the sub-network data communication device is selected from a group that It consists of a local area network, a wireless LAN, the Internet, an optical waveguide, and any combination thereof. The reactive power controller according to any one of the preceding claims, wherein the at least one sub-network controller (801, 802, 803) is provided as a primary sub-network controller in a sub-network and At least one additional sub-network controller is provided as a secondary sub-network controller in at least one second sub-network, the primary sub-network being provided to control the at least one secondary sub-network controller. 12. A wind farm, comprising: a wind farm network connected to a power supply network (900) and comprising at least two sub-networks (300, 400, 500) and a collecting part (905), in which at least two wind turbines (301 , 401, 501) are connected to each sub-network (300, 400, 500), in which the at least two sub-networks (300, 400, 500) are connected to the collecting part (905) and in which the part collector (905) establishes the connection with the power supply network (900); Y a reactive power controller according to any one of the preceding claims.